In reheated condition, as in multipass welding used in this work, the precipitation of secondary austenite, γ2 can occur as consequence of the dissolution of the intragranular nitrides. This chromium nitride precipitation has been shown to compromise the corrosion resistance and the toughness of DSS as discussed in this paper.

The effect of SO2 in the flue gas is investigated to evaluate its role on high temperature corrosion of superheaters under conditions mimicking biomass firing. Results show that when a deposit is absent, SO2 minimizes corrosion attack. Deposit (KCl) particles are sulphated due to the presence of SO2 in the flue gas and the resulting corrosion attack on deposit-coated samples involves severe local pitting, which is minimized when HCl is added to the flue gas.

Two inhibitors formulations have been investigated for the inhibition of mild steel in 15 and 20% HCl solutions at 65 and 90 °C. One of these formulations is composed mainly of coal tar distillation products and the second from the aqueous extract of ginger. The results showed decrease of corrosion rate and increase of the inhibition efficiency with increasing the concentration of the two inhibitors.

A new kind of multi-electrode sensor was developed for the study of under deposit corrosion. The electronic resistance method and zero resistance ammeter technique were used for the monitoring of corrosion depths and galvanic currents. The sensor system showed a wider application range compared with traditional electrochemical methods. The mineral deposit and heterogeneous distribution of the rust layer will cause inhomogeneous corrosion of the steel.

This paper aims at evaluating the influence of Nd addition on the microstructure and corrosion behavior of LAZ832 alloy. The results indicate that Nd addition leads to the coarser of grains and the improvement of corrosion resistance. The improvement of corrosion resistance can be explained from two aspects: First, the purifying effect of Nd increases the stability of the alloy, which is reflected by the value of Rt and Rl. Second, the appearance of Nd2O3 improves the protectiveness of corrosion film, which is reflected by the value of Rf. In addition, Nd addition improves the corrosion resistance, but it doesn't change the corrosion mechanism of the alloy.